I have tried to figure out how this would make a difference and I just can't seem to put my finger on it. I've experimented with both and things in between and it seems to me once the motion starts the wrist position on take back has no effect at all.
I've been telling some of the kids I work with to simply forget about the take back entirely and concentrate on the motion up to contact. I've said once they get the contact part down and can serve reliably they can use whatever take back they want. It just doesn't seem to matter much at all as far as I can tell.
Jolly, in the videos you've sited, it seems that both Roddick and Haas have similar contact and finishes even though they started differently. The Haas video doesn't quite show everything through the contact, but you can see how the arm and wrist turn in the follow through.